fusion technology - safety & environment via e. fermi 45, i-00044, frascati (rome), italy...

Fusion Technology - Safety & EnvironmentVia E. Fermi 45, I-00044, Frascati (Rome), Italy e-mail: [email protected]

ENTE PER LE NUOVE TECNOLOGIE, L'ENERGIA E L'AMBIENTEAssociazione ENEA-EURATOM sulla Fusione

FUSION UNITTECHNOLOGIES DIVISION

Occupational exposure of workers in normal and accidental and post-accident situations.

Task TW5-SL53.4 Deliv. B, C and D and SL53.7 Deliv.B

28th of October 2005

L. Di Pace, T. Pinna, M.T. Porfiri

Task TW5-SL53.4 Deliverables:

B. Safety analysis of failures and consequences during

maintenance. (T.

Pinna)

C. Occupational exposure and radioprotection in

normal operation and during maintenance. (M.T.

Porfiri)

D. Occupational exposure and radioprotection in post

incident-accident intervention. (T.

Pinna)

ORE studies for EISS5 Task TW5-SL53.4 B, C & D Cadarache – October 2005

Del. B - Safety analysis of failures and consequences during maintenance

Maintenance activities will be assessed in order to identify a representative set of failures that could occur during these plant states and that could generate injury or over-exposure to workers.

Consequences will be qualitatively described.

Completeness of the set of accidental situations considered will be substantiated.

Needs of disposals for post-incidental and post-accidental intervention will be checked.

Consequences of remote handling equipment failures will be considered.


Del. B - Safety analysis of failures and consequences during maintenance

Maintenance activities will be assessed in order to identify a representative set of failures that could occur during these plant states and that could generate injury or over-exposure to workers.

Consequences will be qualitatively described.

Completeness of the set of accidental situations considered will be substantiated.

Needs of disposals for post-incidental and post-accidental intervention will be checked.

Consequences of remote handling equipment failures will be considered.


The Reference set of maintenance activities (for which the safety assessment will be performed) will be identify on the base of the results obtained in the Task SL53.4 Deliverable A (CIEMAT) where “The outline of the description of the maintenance programme will be provided”.

Del. C - Occupational exposure and radioprotection in normal operation and during maintenance

The influence of Design Change Recommendations,

not yet assessed, on ORE

The impact of the design updating on the complexity

of the maintenance procedures will be highlighted


Sample from Gordon’s document: Occupational Radiation Exposure Implications of Design Change Requests


1 Modification of the Cryostat Design (DCR-01)

1.1 Brief summary of design change

[M Huguet, Cryostat design: Summary of discussions and conclusions, October 2001] Replacement of the self-supporting cylindrical section of the cryostat by a cylindrical section which is connected to the bioshield at the cryostat penetrations. Motivation of design change: Reduction of the cylindrical shell thickness (to about 20 mm) cost reduction. Simplification of the cylindrical shell design by eliminating stiffening ribs. Possibility to increase the space available inside the cryostat for coil maintenance by

elimination of ribs and by moving the cryostat shell close to the bioshield. Elimination of the relative displacements between the cryostat and the bioshield

elimination of the elastomer bellows between the cryostat and the bioshield cost reduction.

This proposal was dropped at the Design Review Meeting 22-26 October 2001 due to added complexity in construction and other reasons. 1.2 Occupational radiation exposure implications

1.2.1 External dose rate

The expected result of the design change is an increase in dose rates external to the cryostat due to thinner cryostat walls (assuming no other shielding is provided in the cryostat). 1.2.2 Contamination and tritium level

The expected result of the design change is no change in tritium or other contamination levels in accessible areas. 1.2.3 Worker activities

There may have been an improvement in worker accessibility for (infrequent) maintenance within the cryostat; however, the space between the cryostat and bioshield would have been decreased making leak detection and inspection of the cryostat more difficult.

Del. D - Occupational exposure and radioprotection in post incident-accident intervention

Postulated Initiating Events (PIEs) and elementary

failures concerning main ITER systems (e.g.: Tokamak

Water Cooling Systems, Tritium Systems, Remote Handling),

will be investigated in order to identify the more

challenging events in terms of worker exposures in

post incident-accident interventions.

A draft evaluation of possible doses will be estimated

for the most hazardous situations.


Del. D - Occupational exposure and radioprotection in post incident-accident intervention

Postulated Initiating Events (PIEs) and elementary

failures concerning main ITER systems (e.g.: Tokamak

Water Cooling Systems, Tritium Systems, Neutral Beam

Injectors, Remote Handling), will be investigated in

order to identify the more challenging events in

terms of worker exposures in post incident-accident

interventions.

A draft evaluation of possible doses will be estimated

for the most hazardous situations.ORE studies for EISS5 Task TW5-SL53.4 B, C & D Cadarache – October 2005

Outcomes obtained by the FMEAs will be used to identify PIEs (accident events) and incidental situations to be studied. Elementary failures and related consequences, as reported in the FMEA tables will be checked in order to point out events that could induce ORE increasing

Int.Rep. on Deliv. B from Deliv. A results to 6 months later

Int.Rep. on Deliv. C 0 months to 12 months after signature

Int.Rep. on Deliv. D 0 months to 12 months after signature

Task TW5-SL53.4 Planning


fusion technology - safety & environment via e. fermi 45, i-00044, frascati (rome), italy...

Documents